Great developments have been underway in recent years in the field of data storage devices. The seminal patent application PCT/SG00/00029 introduced the concept of a data storage device which includes a housing having an integral USB plug and within the housing a non-volatile solid state (i.e. integrated circuit-type) memory device, such as a flash memory. The first such devices, launched in late February 2000 had a capacity of 8 MB, and much higher capacities are available now.
In parallel to this, there has been rapid improvement in hard disk technology, and portable data storage devices of at least several GB are now available, having a size comparable to the solid-state portable data storage devices discussed above.